This is the live version from the Arriving Somewhere... dvd, the studio version is 
basically the same
but with a few changes that shouldn't be a problem for you guys to figure out :)
I know Porcupine Tree plays most in Drop D tuning but this one is on standard
(analyzed Steven's position on the dvd)

The intro is done with a reaally cool tone that I have no idea how Steven gets, and 
volume swells...
lots of sustain and vibrato too.
e|---------14--15--14-12------17----19-------------------------17---14--15-14-12\---|
B|-12-------------------------------------17---13b15---8b10-------------------------|
G|----------------------------------------------------------------------------------|
D|----------------------------------------------------------------------------------|
A|----------------------------------------------------------------------------------|
E|----------------------------------------------------------------------------------|

[VERSE 1]

e|-------------------------------------|
B|----3--------1--------2--------3-----|
G|------3--------1--------2--------3---|
D|-------------------------------------|
A|-3--------1--------0-----------------|
E|----------------------------1--------|

e||----------------------------------------||
B||----------------------------------------||
G||o-2------------------------------------o||
D||o-2------2------3----------------------o|| x4
A||--0------2------3--------3-3-3p2-2------||
E||---------0------1------3-----------3----||


[VERSE 2]

e|-------------------------------------|
B|----3--------1--------2--------3-----|
G|------3--------1--------2--------3---|
D|-------------------------------------|
A|-3--------1--------0-----------------|
E|----------------------------1--------|

e||----------------------------------------||
B||----------------------------------------||
G||o-2------------------------------------o||
D||o-2------2------3----------------------o|| x3
A||--0------2------3--------3-3-3p2-2------||
E||---------0------1------3-----------3----||

e|-----------------------------------------|
B|-----------------------------------------|
G|--2----------------------------------2---|
D|--2------2------3--------------------2---| hold the A chord
A|--0------2------3--------3-3-3p2-2---0---|
E|---------0------1------3-----------3-----|


Again with the cool tone, volume swells, and the vibrato
e|----------------------------------------------------------------------|
B|-10----12----13----17--15----17--20------20---13--15--12--13--12------|
G|-------------------------------------19---------------------------12--|
D|----------------------------------------------------------------------|
A|----------------------------------------------------------------------|
E|----------------------------------------------------------------------|

e|-------------------------------------------|
B|-5-----8---10---12---13---12---10---(12)---|
G|-------------------------------------------|
D|-------------------------------------------|
A|-------------------------------------------|
E|-------------------------------------------|


Steven switches to a clean tone for the solo
e|------------------------------------------------------------------------|
B|----10----10/12-12h13-12------------------------------------------------|
G|-9------9-----------------12--------------------------------------------|
D|------------------------------12-10-9------------9-9h10-9--------9-10---|
A|---------------------------------------12--12-12-----------12-12--------|
E|------------------------------------------------------------------------|

e|----------------------12--12/15---------------------------------------------|
B|----10----10/12-12h13------------15-17--17/18--17---------------------------|
G|-9------9------------------------------------------17-17/19--16-17--16\12---|
D|----------------------------------------------------------------------------|
A|----------------------------------------------------------------------------|
E|----------------------------------------------------------------------------|

And then the solo is repeated but this time on the overdriven channel.


e||----------------------------------------------------||
B||----------------------------------------------------||
G||o-9---9-9-9---9-9-9---9-9-9/12-12-12\7-7-7/9-9-9---o||
D||o--------------------------------------------------o|| x3
A||----------------------------------------------------||
E||----------------------------------------------------||

e|---------------------------------------------------|
B|---------------------------------------------------|
G|--9---9-9-9---9-9-9---9-9-9/12-12-12\7-7-7/9-9-2---|
D|-----------------------------------------------2---| Hold the A chord
A|-----------------------------------------------0---|
E|---------------------------------------------------|